I see lots of posts about updates failing. And always the same guidance; reset to factory defaults. That doesn't work. There are a lot of people stuck at the 02.08.29.00 version of the firmware. Verizon lists the latest version as 02.08.59.00 and details a lot of new features and improved performance on Verizon's own web pages at .../support/verizon-jetpack-ac791l-update/. But when you try to have the device check for updates you get an error with no details.
Come on Verizon. Just post a link to the firmware file. The device admin page allows users to update via a downloaded file. Quit giving everyone the run around, just make the file available already. How about a little decent customer service here?